I think the issue is what would her powers be? I mean I know her mutant powers, but how would they be usable in the game? Sure, she could look like a bad guy maybe, but there's not enough versatility to that. And with limited amounts of characters you can play as, I'd rather play as Nightcrawler and other characters whose powers transfer amazingly into gameplay.
"Is this a joke? Because if it is, it's both funny and well-executed."
I agree. It would've been cool to see Mystique as a playable character. As far as her powers are concerned, maybe she could've been a combination of Nick Fury from MUA and the Mystique boss character from X-men Legends 1. I have no idea as to what her Xtreme would be like however.
At least she's playable in the Next Dimension games, but I do agree they could've done her more justice in this series. Now that I think about it, I thought being able to play as the bosses in the danger room mode wasn't all that bad. It would've been a little better if they were available in all of the modes instead of the one where you have less than two minutes to play. Of course it got worse when this game came out. No Stryfe, Sinister, or Archangel.
I don't think she would translate very well to a game like this- she would just be person with a gun. I'd prefer a stealth/rpg type game-that would be awesome!